1. Field of the Invention
The present invention relates to an image blur prevention apparatus for preventing an image blur in a camera, an optical device, or the like.
2. Description of the Related Art
In a conventional image blur prevention apparatus of this type, the influence of a hand fluctuation of a photographer on an image formed on a film surface can be eliminated by the following correction operation. As shown in FIG. 8, when a release button 51 on a camera body 50 is operated, a correction optical system 56 is eccentrically driven in a predetermined direction within a plane perpendicular to the optical axis or tilted with respect to a plane perpendicular to the optical axis via independent correction driving means 54 and 55 on the basis of outputs from sensors 52 and 53 for detecting angular fluctuations about predetermined rotation axes Y (yaw) and P (pitch) shown in FIG. 8.
When the release button 51 is released, the outputs from the sensors 52 and 53 are immediately disconnected from the correction driving means 54 and 55. As a result, the correction operation of the correction optical system 56 is stopped, and image blur correction on the film surface is completed.
In the above conventional method, the correction operation of the correction optical system 56 is stopped immediately after the release button 51 is released. With this operation, for example, in a photographic mode of performing an AF operation a plurality of numbers of times by operating the release button 51 as in the case of depth-of-field-priority AE photography, since an operation of "half press.fwdarw.release" of the release button 51 is repeated, the process of "correction operation.fwdarw.correction stop" is repeated accordingly.
In a device which allows the photographer to check the actual state of an image blur prevention operation through a finder, e.g., a single-lens reflex camera, or a video camera, the influence of a hand fluctuation on an object image which can be observed through the finder decreases and increases irregularly. The resultant image exhibits great discontinuity. This makes the photographer feel a sense of incongruity.
When a correction operation is to be completely stopped, a member having a mechanical lock mechanism operates to mechanically lock the correction optical system 56. This operation, however, requires a time of several 10 to several 100 msec. For this reason, if image blur prevention is stopped immediately after the release button 51 is released, the release time lag is prolonged in a pseudo-continuous shooting operation performed by repeatedly operating the release button 51.